Originally Posted by TheHoneyBadger

Update time. So, after doing the tundra 231 upgrade i never liked how soft my brake pedal was, Despite bleeding the system and verifying that everything was adjusted and working properly. I then started to get gremlins in my ABS system. On several occasions, on dry pavement, under light braking, my brakes would go into full lock accompanied buy harsh grinding sounds. no amount of pedal pumping would unlock them. Scarry stuff, went skidding though an intersection on one of those occasions. Luckily, no one else was in the intersection. Started checking my system out. Sensors and pump all in perfect order, no ABS light on, ever (yes i verified that the indicator was working correctly also). Several people have had this same problem and the cause seems difficult to pin down. So, being that this was my first vehicle to ever have ABS, I'm used to non ABS and had no problem yanking the fuse and not looking back. This however highlighted the fact that my stock master cylinder seemed to not be able to keep up with the larger front calipers. It seemed like when my brakes would lock, the master couldn't move enough fluid to unlock them. So, after some research, i found a few options for upgrades. I ultimately decided on a master/booster combo from a 97 t100. 1ton. My booster was in working order, but the 1 ton master is a 4 bolt, so i grabbed both to simplify things. The master has a 1 1/16" bore vs the stock 1". This doesn't seem like a huge increase, but i felt like i didn't need much considering my rears are still stock. For whatever reason no one sells the 1ton master with the reservoir locally. After eyeballing it though, i was pretty sure it was the same as the one in the 4runner. I swapped them in today without any issues. The reservoir fit perfectly, the booster pedal linkage rod is the same length and thread as stock, the brake lines are the same thread. Results; much firmer, better feeling brake pedal. I even locked it up on the way home (cat ran out in front of me and it was raining) and was able to unlock and stop the truck with a quick half pump. Very pleased overall with the upgrade, and would suggest it to any one else with the same issues.

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